The present invention broadly relates to passenger transport installations, especially escalators and, more specifically, pertains to a new and improved construction of an escalator step and also pertains to a new and improved method of protecting lateral edges of transport installations.
In the context of this disclosure, the term escalator step refers to any support member for the transport of passengers or articles by means of a sequential train of such support members. A preferred application of the inventive step member is in passenger escalators.
In its more particular aspects, the invention relates to an escalator step of an escalator step run comprising a plurality of escalator steps and two continuous transporting or traction means, which escalator step run is guided between two stationary skirt panels and which escalator step possesses tread edge members protruding or projecting beyond, i.e. above, the tread surface on both lateral sides.
It is known that in escalators, a latent danger of jamming prevails, above all for flimsy footwear, between the moving step and the stationary skirt panel. Jamming accidents usually arise then when a passenger stands laterally so close to a limit of the tread surface of the step that a shoe brushes against the stationary skirt panel mounted laterally of the step. In addition to the thus resulting friction counter to the direction of travel, at the locations where the step risers either retract or deploy, there arises a relative motion transverse to the direction of travel resulting in friction transverse to the direction of travel. This motion and the therewith associated friction arise at either the upper or the lower transition or landing region of the escalator, depending on the direction of travel. This motion can draw flimsy footwear in between the moving step and the stationary skirt panel.
In other words, the present invention relates to a step or step member for an escalator in which an escalator step run comprising a plurality of such step members and two continuous traction means is guided between two stationary skirt panels. The step member comprises a step body having a tread surface, two lateral sides and at least one lateral side wall. The step body is provided with a respective tread edge member arranged at each of the two lateral sides and projecting above the tread surface.
Expressed in a different manner, the step or step member of the present invention is for a transport means, especially passenger transport means such as escalators and moving sidewalks or walkways. The step member comprises a step body having a substantially horizontal tread surface and two lateral walls. The step body is provided with a tread edge member arranged at least at one of the two lateral walls for performing extension and retraction motions relative to the step body such that each tread edge member projects above the substantially horizontal tread surface in an extended position thereof and such that each tread edge member is substantially flush with the substantially horizontal tread surface in a retracted position thereof.
The present invention also relates to a transport means, especially a passenger transport means such as an escalator or a moving sidewalk or walkway. The transport means comprises continuously circulating traction means having a predetermined path of travel. The continuously circulating traction means comprise chain wheel axles extending transverse to the predetermined path of travel and each having two ends. The continuously circulating traction means comprises link members extending substantially parallel to the predetermined path of travel and each having a first end and a second end. A respective link member of the link members is attached to each end of the two ends of each chain wheel axle and fixed against rotation relative thereto.
The method of the present invention is for protecting the lateral edges of transport means comprising step members and continuous traction means having discrete link members, especially passenger transport means such as escalators and moving sidewalks or walkways. The method comprises the steps of providing each step member with a tread edge member arranged at least at one of two lateral walls of the step member for performing extension and retraction motions relative to the step member such that each tread edge member projects above the substantially horizontal tread surface in an extended position thereof and such that each tread edge member is substantially flush with the substantially horizontal tread surface in a retracted position thereof.
Various developments have become known by means of which it has been tried and is still being tried to obviate the danger set forth above. One of these developments which is known from the U.S. Pat. No. 4,236,623, granted Dec. 2, 1980 consists in raising the lateral portions of the step tread or surface by wedging a plastic profile or rib into the outermost two grooves of the tread so that this portion of the step is rendered uncomfortable to escalator users such that they will stand on the planar tread surface adjacent this raised rib. The wedged plastic profile or rib additionally possesses a gentle inclination on the surface facing away from the skirt panel. A shoe nevertheless brought to bear on this location also assumes a slight inclination or canting. If the shoe also simultaneously bears against the skirt panel, a portion of the ensuing horizontal force will be taken up by the raised step edge and the friction on the skirt panel and thus the danger of drawing the shoe in between the step edge and the skirt panel is reduced.
A further development of this nature is known from the U.S. Pat. No. 4,413,719, granted Nov. 8, 1983 in which, inter alia, plastic components are set in a guiding fashion on the lateral tread sides which slidingly bear against the skirt panel. The plastic components possess a low coefficient or friction and fully take up the play between the step and the skirt panels, thus greatly reducing the danger of flimsy footwear being drawn in.
However, both inventions have the disadvantage that the raised side portions of the steps or treads require more lateral space when running through the upper and lower comb plates and the danger of jamming is substantially increased when running into a comb plate when a wedged plastic component loosens during the course of time or is missing from the step tread for any reason.